Molecular characterization of the following events is the object of our current work: (1) conversion of the phi X174 single strand to the replicative form, (2) purification of the E. coli DNA replication proteins: products of the dna A, B, C and G genes (3) replication of the "eclipsed" phi X virion, (4) uniqueness of the origin and termination on the phi X viral strand, (5) M13: SS yields RF conversion with soluble enzymes, (6) initiation events in conversion of M13 SS yields RF, (7) multiplications of the M13 duplexes, and (8) synthesis of M13 viral strands.